Co-cultivation of antifungal Lactobacillus plantarum MiLAB 393 and Aspergillus nidulans, evaluation of effects on fungal growth and protein expression.

The fungal inhibitory effects of strain Lactobacillus plantarum MiLAB 393, producing broad-spectrum antifungal compounds, were evaluated. A co-cultivation method was set up to monitor effects on fungal growth and protein expression of growing Aspergillus nidulans with L. plantarum MiLAB 393. The effects of inhibitory metabolites produced by L. plantarum MiLAB 393, cyclo(l-Phe-l-Pro), lactic acid and 3-phenyllactic acid, were also investigated by addition of pure compounds to the growth medium of A. nidulans. The co-cultivation strongly affected the morphology of the fungal mycelium and decreased the biomass to 36% of control. Co-cultivation with Lactobacillus coryniformis MiLAB 123 gave only marginal morphological changes and minor biomass reduction, suggesting specific effects of L. plantarum MiLAB 393. The amount of several A. nidulans-proteins was increased during co-cultivation and by all of the inhibiting substances. This study shows that the growth of A. nidulans is inhibited during co-cultivation with L. plantarum MiLAB 393 and that the expression of fungal proteins is altered.